Role of fusaricidin a against pokkah boeng disease of sugarcane by affecting fungal signalling pathways and inducing Fusarium sacchari conidia death

BACKGROUND: Sugarcane pokkah boeng disease (PBD) has emerged as a global agricultural challenge, threatening sugarcane productivity and sustainability. Amid growing concerns about excessive chemical fungicide use, biocontrol strategies have gained traction as environmentally-friendly alternatives. This study aims to establish the theoretical foundation for fusaricidin A against PBD, exploring its antifungal mechanisms and efficacy in managing the disease caused by Fusarium sacchari. RESULTS: Fusaricidin A suppressed germination of F. sacchari conidia and provided protective efficacy against PBD in glasshouse assays. With the treatment of fusaricidin A, the conidia of F. sacchari were not well-stacked, even ruptured and collapsed; the cell membrane showed irregular structure and no clear discernable level, with uneven thickness. Notably, treated cells displayed a significant increase in liposome accumulation. Fusaricidin A induced significant alterations in cellular physiology and gene expression in F. sacchari conidia. Fusaricidin A caused plasma membrane permeability disruption and enhanced spore apoptosis rate, accompanied by excessive reactive oxygen species (ROS) production in mitochondria. Transcriptomic analysis (RNA-seq) and quantitative reverse-transcription (qRT)-PCR revealed upregulated expression of antioxidant genes GSH1, GSH2, SOD1 and SOD2, indicating a cellular stress response to ROS overload. Concurrently, downregulated Mkk1, Mpk1 and Swi4, which are well-characterized core genes in the cell wall integrity signal pathway, were identified, suggesting that fusaricidin A impairs conidial cell wall stability. CONCLUSION: The potential antifungal mechanisms of fusaricidin A involve multifaceted antifungal effects through membrane damage, ROS-mediated oxidative stress and disruption of cell wall integrity regulatory pathways. This study provides valuable insights for the effective management of plant fungal diseases and supports sustainable agricultural development. © 2026 Society of Chemical Industry.